Apparatus and method for reproducing surface contours



Aug. 10, 1954 J J. E. DAVIS 2,686,101

APPARATUS AND METHOD FOR REPRODUCING SURFACE CONTOURS Filed June 11,1951 6Shets-$heet 1 Fig.5.

ATTORNEY J. E. DAVIS 2,686,101

ING SURFACE CONTOURS APPARATUS AND METHOD FOR REPRODUC 6 Sheets-Sheet 2Filed June 11, I951 INVEN L/OH/V E. flAv/s ATTORNEY ill 7 3 6 "m 7 m" 6:5 5 5 n. T" 4 s- 10, 1954 J. E. DAVIS 2,686,101

APPARATUS AND METHOD FOR REPRODUCING SURFACE CONTOURS Filed June 11,1951 6 Sheets-Sheet 3 INVENTOR Ja/m 5 5/1105 ATTO R N EY 1954' J. E.DAVIS 2,686,101

APPARATUS AND METHOD FOR REPRODUCING SURFACE CONTOURS Filed June 11,1951 6 Sheets-Sheet 4 Jam/ 15 04w:

OURS

J. E. DAVIS Aug. 10, 1954 APPARATUS AND METHOD FOR REPRODUCING SURFACECONT 6 Sheets-Sheet 6 Filed June 11, 1951 Fa Tiql 1-.

INVENTOR Jay/V5041:

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Patented Aug. 10, 1954 APPARATUS AN]? METHOD FOR REPRODUC- ING SURFACECONTOURS John E. Davis, Oakland, Calif. Application June 11, 1951,Serial No. 231,031

2 9 Claims. 1

This invention relates to apparatus for tracmeasuring and reproducingvariations in contours on different types of specimens, is particularlydirected to devices and methods for accurately charting microscopiccontour variations appearing on such specimens.

For many years a need has existed for some type of apparatus which couldreadily anal xze surface irregularities. Such apparatus is not onlyessential for examination or the surfaces of certain precision tools orequipment, but is of extreme importance in the fields of criminology inwhich technicians are often required to examine, analyze and comparemarkings produced by certain cutting and scraping tools on some object,or th striations created on bullets after being fired through rifledbores. Heretofore, it has been the standard practice or" persons engagedin s ich work to use the familiar comparison microscope in which theevidentiary bullet or other device may be compared with a test bullet,the markings of each specimen may be compared, and a person skilled inthe field may determine whether or not the marks are substantiallyidentical and thereby ascertain the possibility of whether the same gunor tool created the markings on both specimens. comparatively recently,some advancement has been made in the field of surface or contouranalysis by the use of profilographs or similar apparatus in whichsurface depressions and elevations are magnified and recorded. In thismanner, a convenient picture is obtained for purpose of analysis and/orcomparison with other pictures for determining similarities anddistinctions. These devices, while constituting an improvement overpreviously used methods and machines, possessed a number ofdisadvantageous features, among them being their high cost ofmanufacture and maintenance, complicated structural arrangements leadingto breakdowns and possibly incorrect results, inability to accuratelyproduce a true cross-sectional con tour of a bullet or other cylindricalor spherical object, distortion or reproduction, cutting or other injuryto the object being analyzed, as well as other factors contributing totheir limited utility, especially for police investigation work.Although the present application may give particular emphasis to the useof the apparatus and method of my invention in connection with the art,that such discussion scale for subsequent analysis or comparison withother reproductions.

A further object-of the invention is to provide apparatus of the abovetype which is light weight, which contains a minimum of operating parts,which can be constructed at a reasonable cost, and which is capable ofoperating over extended periods of time without requiring any specialservicing or other extensive repair or maintenance,

Yet another object of my invention is to provide a contour reproducingdevice in which the specimen is moved in timed relationship to movementof the photographic film on which the contour image is produced, and inwhich the image corresponds to the general shape of the specimen beingtested.

A still further vide apparatus invention is to provide character inwhich the mechanism'proceeds over the specimen apparatus of the abovetracing contour in some prior art devices.

Still another object of the vide apparatus of the type described inwhich repeated reproductions of the surface contour may be made withoutcreating new markings on invention is to prothe specimen and withoutrequiring the use of Another object of this invention is to provide adevice in which a pair of parallel spaced images of the contour of anobject may be produced on a single film whereby a careful check may bemaintained as to any possible inaccuracies existing in the mechanism orin the original image.

A further object of my invention is to provide a process for reproducingsurface contours of some object in which the photographic film isarranged to intercept light rays which are caused to fluctuate accordingto the irregularities appearing on the contour of the specimen beinganalysed, and in which the film is caused to move in synchronism withthe specimen.

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth in the followingdescription of the preferred form of the invention which i illustratedin the drawings accompanying and forming part of the specification. Itis to be understood, however, that variations in the showing made by thesaid drawings and description may be adopted within the scope of theinvention as set fotrh in the claims.

Referring to the drawings:

Figure 1 is a front perspective view, diagrammatic in character,illustrating the principles of operation of the apparatus of myinvention.

Figure 2 is a front elevational view of the apparatus.

Figure 3 is an end elevational view, portions of the drawing beingbroken away in order to more clearly disclose the details of internalconstruction.

Figure 4 is a sectional view taken in the plane indicated by the line ii of Figure 2.

Figure 5 is a perspective view of a portion of the centering apparatusfor the bullet holding mechanism.

Figure 6 is a perspective view of the clutch arrangement interposedbetween the specimen and the photographic film.

Figure 7 is a rear perspective view of the film holder and easing.

Figure 8 is a perspective view of the adjustably positioned fulcrum forthe lever mechanism of the present invention.

Figure 9 is a cross-sectional View taken substantially in the planeindicated by the line 9-9 of Figure 2.

Figure 10 is a cross-sectional view taken in the plane indicated by theline iii-iii of Figure 2.

Figure 11 is a sectional view taken in the plane indicated by the line ill l of Figure 10.

Figure 12 is a plan sectional view taken along the plane 12-42 of Figure2.

Figure 13 is representative of a film produced by the present apparatusand indicating striation on a typical bullet.

Figure 14 is a front elevational view of another embodiment of theinvention utilized in making substantially flat surface analysis.

Figure 15 is a plan view of the structure disclosed in Figure 14.

Figure 16 is a plan View taken in the plane indicated by the numerals58-4 6 of Figure 14.

Figure 17 is a cross-sectional view taken in the plane indicated by thenumerals i'i-i'i of Figure Figure 18 is an elevational view of the imagebearing film illustrating a sample flat surface contour.

In broad terms, the apparatus of the principal embodiment of theinvention as disclosed in Figures 1 through 13 of the drawings comprisesmechanism for holding a spherical or cylindrical object such as abullet, a tracing device arranged to continuously follow the peripheralsurface of the object as the latter is rotated, means for amplifying thecontour irregularities as indicated by the tracing device, and means forrecording such amplified irregularities in proper relative positions onphotographic film. The embodiment disclosed in Figures 14 and 15 isparticularly adapted for examination of relatively fiat surfaces, andlikewise utilizes a holding mechanism and a comparable tracer andamplifying means, the chief distinctions between the embodiments lyingin the method of mov n the object past the tracing apparatus and thearrangment of the photographic film on which the contours arereproduced. In both embodiments, the amplification of contourirregularities preferably occurs in two stages, the initial stageresultin from a mechanical advantage created by the arrangement of thetracing mechanism, and the latter being occasioned by the use ofappropriate lenses, and as will be more fully described, each of thesearrangements may be selectively varied to produce the desired degree ofcontour magnification without enlargement of the general shape of thespecimen.

Apparatus to carry out the foregoing might be constructed in a number ofdifferent ways, but I prefer to utilize the arrangement of partdisclosed in Figure 1 of the drawing which possesses all of theadvantageous characteristics set forth in the objects and features ofthe invention. The apparatus includes holding means I5 for a bullet 16or other specimen to be analyzed. A lever, generally indicated by thenumeral IT is equipped adjacent one end thereof with a tracer arm,preferably in the form of a needle 18, designed to constantly engage theperipheral surface of the specimen as the latter is rotated, the otherend of the lever being arranged to intercept a beam of light from alight source i9. As will be seen, the light beam is projected onto anannular sheet of photographic film 2| which is rotated in synchronismwith the specimen, and due to the bidirectional linear movement of thetracer needle as the latter rides over the surface irregularities of thespecimen, portions of the light beam will be prevented from strikin thefilm, with the result that the image or unexposed portion of the filmwill exactly conform to the cross-sectional contour of the specimen butwith amplified contour variations. To simplify and make the constructionmore compact, it is preferable to mount the film 21 in axial alignmentwith the specimen, and it is therefore necessary to provide suitableprisms or mirrors 22 and 23 to properly reflect the light beam from itssource to the film, although it is believed clear that if desired, thefilm could be arranged in alignment with the light source and thusdispense with the necessity of such prisms or other refractory media.

As will best be seen in Figure 13, the film sheet 2! is of generallycircular form and is provided with a centrally disposed opening 24 whichis arranged to fit over a rear shaft 26, the latter extendingsubstantially horizontally of the apparatus. Mounted for rotation withthe shaft 26 is a disk-like film-supporting element 2?, the connectionbetween the shaft and element being made in any convenient manner suchas by providing threads 28 intermediate the ends of the shaft andreleasably securing the film disk thereto by clamping the latter betweena nut 29 threadedly engageable with the shaft and a collar member .31provided with a suitable gasket 32.

5. Photographic film must be maintained in darkness to preventaccidental exposure thereof, and it is therefore necessary to provide asuitable housing for the disk 2'! and its associated film. Withparticular reference to Figure 7, it will be seen that the housingcomprises a pair of substantially symmetrical rectangularly shapedboxlike sections generally indicated by the numerals 33 and 3:3, theopen ends of each of the sections cooperating and interfitting toprovide a substantially enclosed housing for the film. Adjacent the openends on each side panel of the sections is mounted one half of a splitbearing 36, the adjacent halves from the respective sections cooperatingto define a bearing seat for the shaft The sections 33 and 34 areprovided with generally conventional interfitting members 31 latter, andto releasably secure the sections together, suitable latch fasteners 38are disposed adjacent the open. ends of the sections and arranged to beinterconnected when the sections are placed in their immediatelyadjacent position. By constructing the housing and shaft support in thismanner, it is a simple matter to either place or remove the film 2i fromthe disk 21. To perform the foregoing, it is only necessary to releasethe latches 38 and raise the upper housing section 33 by means of handle39, the shaft 28 and the film disk then being readily available forlifting from the lower split bearing supports. The film may bereleasably secured to the disk 21 by means of any suitable adhesive andas the disk is rotated on the bearings different portions of the filmwill be sequentially passed opposit rear panel 42 of the housing section33. By providing a slide element 43 adjacent panel 52 and over the slotlight entering through the latter may be either completely out off orcontrolled to vary the dianietrical extent of the exposed portion of thefilm. The element i3 merely comprises a fiat rectangular plate arrangedfor vertical movement in a bracket as provided with a slot it alignedwith the slot If desired, suitable indicia sl may be imprinted on thebracket whereby the operator may readily ascertain the size of theresultant exposed film portion.

The foregoing description has set forth the details of construction ofthe rear portion or film supporting mechanism of my invention, and Iwill now describe the manner in which the bullet or other specimen isheld in the apparatus and the means whereby the specimen and film may besimultaneously rotated in order to produce on the film proper angularrelationships of all surface irregularities appearing on the specimen.

The bullet or similar specimen is disposed in general axial alignmentwith the rear shaft 26 and may be reieasably secured for rotation insuch alignment by numerous methods, such as by a conventional chuckdevice. However, in order to simplify the apparatus, as well as toprevent mutilation of the specimen, I prefer to mount the bullet in acup-lik member 48 in which is placed a quantity of wax is or similarpliable material, such material furnishing a support for the bullet.Member 28 is provided with a stud 55 which is mounted in a centeringhead 52 by means of which the axial centerline of the bullet may beselectively moved in a horizontal or vertical plane. As here shown, andwith particular reference to Figures l and of the drawings, thecentering head comprises a pair of adjacent disks 53 and 54 which aregenerally axially aligned with the shaft 26 and bullet I6. The frontdisk 53 is provided with an aperture 56 to receive the stud 56 of thebullet holder, and a pair of normally related dove tailed tongues and 58are secured together and arranged for axial sliding movement incorrespondingly shaped dove tailed grooves 5| and 62 formed in disks 53and M respectively. The distal ends of the tongues terminate short ofthe ends of the grooves and annular rings 83 and 64 are secured to theperipheral surfaces of the disks by means of screws 56 or the likepassing through flanges i3? and 68. Each of the rings is provided with athreaded aperture 69 arranged to receive a bolt ll whose end bearsagainst an end of its associated dove tailed tongue. Although it wouldbe possible to use two diametrically opposed bolts for positioning thetongues, I prefer to utilize only one bolt on each tongue, a spring 72being interposed between the other end of the tongue and the annularring. The bolt ll is here shown as being provided with an elongatedknurled handle portion for ease in making the necessary adjustments.From the foregoing it is believed apparent that the bullet may bereadily centered by merely tightening or loosening the two bolts iiagainst spring pressure, the corresponding movement of the tonguesimparting like movement to the bullet holding member 23. Variousmodifications could be made of the centering head as will be apparent tothose skilled in the art, but for purpose of explanation, theinexpensive and simple arrangement disclosed herein is deemed adequate.

The centering head is secured to the threaded end 74 of a front shaftthe latter being axially aligned with the rear shaft 25 and arranged tobe rotated therewith. Shaft 76 is mounted for rotation in a pair ofaxially spaced bearings 'i'i secured to opposite sides of a front panelmember l8 constructed of lriasonite, wood or any suitable material. Aspreviously mentioned, rear shaft 23 together with the film disk 2? isdesigned to be removed from the film housing for loading or unloading ofthe him 2!, and it is therefore necessary to provide some clutchmechanism which will effect positive and direct transmission of rotarymovement between the shafts 28 and lb and at the same time permit theaforesaid removal of the former. It is also desirable to provide aclutch which will permit the film disk to be reinstalled in theidentical rotational position relative to the specimen that it had priorto removal. The clutch mechanism best seen in Figures l and 6 comprisestwo axially spaced disks 8! and 82 secured to the rear and front shaftsrespectively means of collars 53 through which set screws 84 arethreadedly engaged to bind the collars to the shafts. The opposed facesof the disks are provided with dogs 35 and 8? and it will be evidentthat if the rear shaft 26 is rotated the dog 35 will engage dog 8'! andeffect rotation of the shaft and the specimen associated therewith, butat the same time permit removal of the rear clutch and its associatedshaft.

Means are provided for imparting rotary motion to at least one of saidshafts. It will be seen that the front supporting is is dis posed in agenerally vertical plane and see ed to a horizontal base member pl alityof the length of front shaft and shaft 26. of side panels 92 forming anopen backed enclosure for the film housing, the greater portion Thelower film housing section 34 is arranged to seat on the base 9| inpredetermined relation to front panel 18, and also mounted on the baseis a suitable source of power, such as a small motor 93 with ahorizontally disposed drive shaft 94. A shaft 86 is journaled insuitable bearings 91 provided adjacent the lower panel portions of filmsection 34, said shaft carrying a friction drive wheel 98 engageablewith the periphery of the film disk 2'! when the latter is seated in thefilm housing. Shafts 94 and 96 also respectively carry interengageablefriction drive wheels 99 and NH, and in this manner, when the motor isactuated, wheel 98 will impart rotary movement to film disk 2! and rearshaft 26, the clutch arrangement imparting identical rotary movement tofront shaft 76, the centering head 52, and specimen l6. Rear shaft 26may also be manually rotated by means of a handle H32 secured to thedistal end of the shaft and positioned exteriorly of the film housing.

It has been previously mentioned that as the bullet l8 and film 2! arerotated, the tracer arm needle [3 continuously engages the peripheralcontour of the specimen, and by oscillating the lever arm ll, the heightof light beam striking the film through the housing slot ll will beraised and lowered in response to similar movements of the lever arm. Asbest seen in Figures 1 and 2, the needle is is angularlydisposedrelative to the vertical plane of the bullet so as to prevent the needletip from sticking or binding in depressions in the bullet periphery.Lever arm H is preferably constructed of balsa wood or similar lightweight material for greater sensitivity, with the fulcrum therefordisposed intermediate the needle 88 and the distal end of the lever atthe light source. Arm ll includes a pair of generally horizontallyextending bowed strips H33 and [05, an opaque plate Hi6 with aknife-like edge H31 on the upper and lower surfaces being mounted on thestrips in substantial registry with the light source and the prism 22.Thus, as the end of the lever moves up and down, the height of the lightbeam will be correspondingly decreased and increased with the resultantsimilarly shaped image being produced on the film. Needle l8 dependsfrom the apex of a V-shaped bracket W8 disposed subjacent and secured tothe strips [93 and te l, this bracket also functioning in the leverbalance control mechanism as will be hereinafter described.

The lever arm ll is provided with a suitable fulcrum in order to impartsubstantially vertical movement of the opaque shield Hi6 upon movementof the needle l3, and such fulcrum includes a pair of needles Hi9disposed on opposite sides of the lever arm which are secured to atransversely extending bridge member ill, the latter being mountedadjacent the upper surfaces of the strip tilt and H35 in any convenientmanner such as by a pair of substantially flat posts H2. The ends of theneedles are supported in cuplike bearings H3, preferably constructed ofglass or agate so as to decrease the friction created therebetween andincrease the sensitivity of the apparatus, and as will be seen, theneedle points are seated in a groove or pointed recess in the bearings.Bearings i it are disposed transversely of the lever arm axis and aresupported on a pair of similarly disposed plates ll l by means ofadjustment screws it threadedly engaged with the plates and a mass ofsealing wax i ll on the upper surface of the plate encompassing theupper end of the screws and the lower portion of the bearings. In thismanner, each bearing MS may be vertically adjusted to insure themaintenance of the bridge member II I in a horizontal'plane and toassist other parts of the mechanism presently to be described incompensating for the size of the specimen being analyzed, and at thesame time permit compensatory horizontal bearing adjustment.

Means are provided for adjusting the plates H4 in both a horizontal andvertical direction to permit the aforesaid accommodation of specimens ofa comparatively wide range of sizes. As here shown, each of the platesus is supported in a generally horizontal plane by a pair of anglebrackets l2i, the latter comprising vertical webs I22 and horizontalflanges 23 disposed below the plane of the plates H4. The flanges I23are positioned subjacent the plates l ill and are arranged to supportthe latter by means of bolts 124 threadedly engaged with a pair of nuts(26 positioned adjacent the upper surface of plate HQ, and the lowersurface of flange 123 respectively, and it is believed evident that alimited amount of vertical adjustment of the plates may occur byscrewing the bolts 124 up or down in the plates and flanges. In order topermit the simultaneous movement of both plates H4 and their associatedbearings, instead of the individual adjustment just described, thefollowing mechanism is utilized. With particular reference to Figures 8and 10, it will be seen that a vertically positioned housing I2? issecured to a plate 128, the latter being mounted in parallel spacedrelation to the panel member 18 by means of a spacer block H9. Thechamber is! defined by the housing 12'! is substantially square incross-sectional form and mounted adjacent the lower end thereof is astationary block [32 provided with an axially extending aperture I33. Astud we having a knurled hand grip 36 extends through the aperture 33and threadedly engages an axially movable block I37 extending beyond theupper end of the housing I21. Due to the presence of a horizontal screw58 in block [32 which engages a peripheral groove I39 in the stud, uponrotation of the latter, the stud will be held in fixed axial position,but will cause the block 131 to selectively move upwardly or downwardlywithin the housing chamber. Secured to the upper end of the movableblock it? is a horizontally disposed casing Ml, similar to the casingI21 and likewise including a stationary block 142, an axially movableblock Hi3 and a knurled ended threaded stud memberi it, the latter alsobeing axially fixed so as to effect horizontal movement of the blockHi3. Casing Hit includes one or more dove-tailed tongues M6 arranged forvertical movement only in similarly shaped grooves H31 in the plate I28,Block 543 extends beyond the end of the casing iii and is secured to theflanges I22 of the angle brackets, one or" the latter being connected tothe block by means of a transverse brace I48. In place of the casing andblocks illustrated, a rack and pinion arrangement could be substitutedtherefor which would permit the combination vertical and horizontalmovement for the lever hanger.

From the foregoing, it will be understood that the bearings H3 whichsupport the needles I09 and act as a fulcrum for the lever arm may befirst moved in a vertical direction by rotation of stud kit whicheffects a raising or lowering of the bracket support block E43 and thuspermits specimens of varying sizes to be engaged by the tracer needlel8; and the bearings may also be moved in a horizontal direction so asto compensate for the vertical movement thereof.

In view of the fact that the fulcrum may be moved with a resultingmovement change in the lever arm, and the specimen will not alwayspossess the same overall diameter, it is necessary to provide some meansfor controlling the balance of the arm so that the tracer needle willalways gently but positively engage the contour of the specimen. Asimple manner of achieving the foregoing is by securing one end of alength of chain I 49 to the end of the lever arm remote from the opaquemember I06 or to the bracket Hi8, and coiling the chain around a drum I!which is secured to a shaft I52, the latter being journaled in panelmember l8 and a bracket itii member 78 which is rotatable from the frontside of the members by I 5 l. Thus, in operation, after the lever armhas been properly adjusted, the hand wheel may be rotated until theupper or lower edge I01 of member I05 is positioned substantiallyopposite to the horizont l diameter of the lenses, thus rotation of thespecimen.

From the foregoing description, the operation may be understood. Afterthe to the rear surface of disk 2? or other specimen properly The lensesI 56, preferably provided with a focusing handle 552 is then verticallypositioned to register with the knife edge 59?. By actuating the motor93, the film and specimen will be simultaneously rotated at a speed ofapproximately 0.1 revolution per minute and the tracer needle moves upor down as it follows the bullet periphery, the distal end of the leverarm carrying member H16 will amplify this vertical movement in an amountdepending, of course, on theposition of the fulcrum of the lever. In anyevent, movement of the member I06 will effectively block certainportions of the light produced from the light source it from enteringthe lenses, and then, the motion of the knife edge will be further magnified by the lenses, which in combination with the prisms or mirrors,will reflect the light through the slot 4! onto the unexposed film. Itwill be apparent that when the tracer needle strikes a depression on thebullet, such as that created by the lands of a gun bore, the knife edgeit? will be raised, with a resulting depression I62 appearing on thefilm due to the vertical shortening of the light rays. Conversely, whenthe tracer needle is caused to rise by passing over an elevation on thebullet, such as that created by the grooves in the gun bore, the knifeedge will be depressed, and a vertically extended light ray will strikethe film and expose a greater portion of the film. Irrespective of theirregularities on the specimen, the corresponding elevations depressionson the film Will be properly angularly positioned, and in order to checkthe accuracy of the produced image, the lenses may be moved until theyregister with the other of the knife edges and the operator may thenrerun the film and specimen, which will produce an image spaced from,but parallel to the previously created image. To facilitate study of theimage, the operator may place greater emphasis on its contour by inkingor otherwise marking the dividing line between the exposed and unexposedfilm portions. An indexing line I83 may also be placed on the film forpurpose of orientation, and due to the arrangement of parts, the filmmay be started at any desired radial position, and may be removed,reinserted, 01' new film substituted therefor without disturbing theset-up of the apparatus and specimen.

It should be clear that by varying the distance between the objectivelenses 56 and the prism or mirror 22, the second amplifying phase may becontrolled. That is, if the distance therebetween is increased, theso-called light lever advantage will be increased, with resultingincreased. vertical magnification, in much the same way as movement ofthe needle bearings l i3 toward the specimen will increase the so-oalledmechanical lever advantage. In the event that the light source is notsufficiently strong, a condens n lens may be interposed between thesource and the lever.

The embodiment of my invention as disclosed in Figures 14. through 17 ofthe drawings is particularly adapted for use in examining relativelyfiat surfaces for minute irregularities, such as those occasioned byvarious tools, and by analysis of an amplified graph of suchirregularities, it is possible to determine the probability of Whether asingle tool made the markings on two test specimens. As previouslymentioned the apparatus for recording the curved or flat contours aresubstantially the same, but in the latter case, the reproductions arearranged to be produced on a film strip iii releasably secured to theperiphery of a drum Hi2 arranged for rotation in a film housing As hereshown, the film housing is substantially square in cross-sectional formand is provided with a vertically extending slot i 1:? on the rear sidethereof, the slot being selectively opened or closed by means of ashutter plate iaE, sim ar to the plate 33 in the other embodiment myinvention. The housing is positioned over a base plate i'ii' by means ofsuitabie brackets I258, and to gain access to the drum the dim thereon,the top cover 11 9 may be removed, carrying with it a shaft iiiljournaled cover bearing i322, and as will be understood, this shaftsupports the drum Within the housing. Shaft i8i extends beyond the uppersurface of the cover and is provided with a hand wheel by means of whichthe drum may be manually rotated so as to bring successive portions ofthe film in registry with the exposure opening or slot I14, and/or toreset the film to correspond to a particular portion of the contour ofthe specimen.

The lower end of shaft l8! extends through the bottom of the housing anda pinion I85 is secured thereto in any suitable manner, and the pinionis arranged to be rotated by a worm gear I84 mounted on a horizontallydisposed shaft I86. By rotating shaft H85, the drum shaft ISI will alsobe rotated, and due to the worm and pinion arrangement, the shaft I8Iand pinion may be vertically moved and removed from the housing andlikewise reinserted and the pinion meshed with the worm gear to bedriven thereby. Shaft I 86 is mounted for rotation in spaced bearingsupports I8? which are secured to base plate Ii! and carries a pluralityof driven gears I88, each of which is of a different size for a purposeto be hereinafter described.

The specimen to be analyzed is indicated by the numeral I89 and isarranged to be supported in generally parallel relation to the baseplate on a movable staging I92, the specimen travelling beneath a tracerarm, such as a needle I93, The staging supports the specimen, and meansare provided for horizontally positioning the specimen relative to thetracer needle so as to permit contour analysis along any linear portionof the specimen. Although it would be possible to clamp the specimen tothe sta ing for movement therewith, I prefer to place the specimen on aplate I94 prov ded with flanges I55 and I91, the flanges being disposedimmediately adiacent the rear and a side edge of the specimen. Thestagin includes a base member I98 supported in vertically ad ustable saced relation to the base plate I11 by means of a threaded stud I99 thelatter being vertically movable relative to a support element 2M, butvertically fixed to the member I 8 in any suitable manner, such as by ascrew 2G2 enga eable in a peripheral notch in the stud. It is believedclear, that bv rotating the stud with the knurled hand grip 2833. thestud will either elevate or depress the member !98 and thus verticallyposition the specimen. The support element 2!!! is provided with adovetailed ton ue 2N5 en a eable with. a sim larly shaped groove 284formed in a longitudinally extending track 2% which is secured to thebase plate, and with this structure. the entire sta ing may be movedalong a predetermined linear path of travel.

To permit the aforesaid horizontal positioning of the specimen. twoplates 2E! and 2% are placed in superimposed relation over the basemember !98. The lowermost plate 201 is mounted in a longitudinal groove26%! provided in the member I93 for bidirectional linear movementrelative thereto. The upper plate 288 is likewise mounted in a groove 2|provided in plate it! for bidirectional linear movement relative to thelatter and transverse to the movement thereof. Each of the plates isprovided with a rack gear 252 extending along a side thereof,corresponding to its direction of movement, engageable with pinions 2 I3 for actuating the rack gears and moving the plates. By rotating thepinion for the plate 2M, plates 2B? and 2&3 will both be moved to theleft or right as viewed in Figure 16, while rotation of the pinion forthe plate 298 will effect movement of this plate along in asubstantially perpendicular direction. Thus, after the specimen isplaced on the plate its, the plate, which is secured to member 2538, maybe moved in a horizontal plane to position a desired portion of thespecimen under the tracer arm or needle.

The tracer arm which includes the needle m3 is supported at the apex ofa V-shaped bracket 2 it which is mounted on a lever EIS, in a mannersimilar to the lever arrangement of the previously described embodimentof the invention. Here, too, a pair of transversely spaced pivots in theform of needles 2!? depend from a bracket 2%8 secured to the lever, theends of the needles bein supportd by the cup-like bearings Bit mountedon parallel spaced me'i hers 22L here shown as angle bars. The latterare superimposed over the staging and are secured to a cross-member 222mounted on a vertical post or standard 223. The distal end of the levercarries a flat opaque element 226, normally positioned opposite anobjective lens 22%, the latter being arranged for vertical positioningon a bracket 212i by means of the rack and pinion 228 or in any othermanner. As will be understood, and as in the previously describedembodiment of the invention, a light source is placed in front of thelever and suitable prisms or mirrors are utilized to direct the lightrays from the source, through the lens, and into the slot Il l of thefilm housing. The fulcrum of the lever 256 formed by the pivot pins ispreferably disposed closer to the tracer needle than to the opaquemember 224, and in this manner, as the tracer needle moves up and downas it follows the surface irregularities on the specimen, the opaquemember will likewise be moved, but to a larger extent, the exact ratioof vertical displacement depending, of course, on the lever length oneach side of the fulcrum. Additional vertical magnification is theneffected use of the lens 226 which, with the prisms or mirrors, notshown, serves as a light beam lever, the degree of magnification beingdependent on the distance between the lens and mirror, or What may betermed the length of the light lever. To provide proper balance for themechanical lever arm 2I5, a length of chain 229 is secured to the endthereof and wound around a drum 23I journaled for rotation in a bracket232 secured to the post 223. As previously mentioned, permitting agreater or lesser amount of chain to hang from the drum will delicatelybalance the lever and control the pressure of the tracer needle on thespecimen.

The foregoing mechanical and light levers will provide the verticalamplification on the exposed film while horizontal magnification willdepend upon the relative rates of movement of the specimen and rotationof the drum on which the film is mounted. By increasing the rotativespeed of the drum, greater horizontal magnification will result, and byproperly regulating the drum speed and the length of the light leverarm, any reasonable combination of vertical and horizontal magnificationis obtainable. Means are provided, in connection with the specimenmoving means, for effecting selected variable ratesof movement of thespecimen anddrum. As previously mentioned, the entire staging issupported for lineal movement along the trackway 265, and such movementmay be induced in the following manner in order to cause speci' mensupported thereon to pass beneath the tracer arm and cause verticaldeflection of the latter. Mounted in a pair of longitudinally spacedbearing brackets 233 which are secured to the base plate ITI i ahorizontally disposed shaft 23d provided with threads 23s for asubstantial portion of its length. The shaft threads are engageable withthreads 23'! formed in a slot 238 of a block 239, the latter also havinga slot 24! for sliding engagement with a support rod 242 secured in thebrackets 233. If desired, the block 239 could be secured directly to thestaging so that rotation of the shaft 234 would impart lineal motion tothe staging and to the specimen thereon. However, I prefer to have thestaging movable independently of the shaft rotation, and I thereforeutilize the block as a holding or braking means against the pull createdby a tension spring 243 secured to a flange 244 of the staging and to afixed portion of the apparatus, such as to one of the brackets I18. Itwill be seen that the spring constantly urges the staging toward theright as viewed in Figures 14 and 15 of the drawing, but as the block isin the path of movement of the staging flange 244, further movement ofthe staging in this direction is prevented until the block is moved byrotation of the threaded shaft 234.

Means are utilized for effecting simultaneous rotation of the shaft 234and the previously discussed drum rotating shaft I56. A drive shaft 246provided with a manually operable handle 241, or which may be connectedto a small motor, is journaled for rotation in spaced bearing brackets248, this shaft being placed generally parallel and spaced to shaft use.At the distal end of shaft 246 is mounted a gear 255 engageable with asimilar gear 25I secured to a parallel stub shaft 252. The stub shaft isjournaled for rotation in a plurality of spaced bearing brackets 253 andis also provided with a worm gear 25% engageable with a bevel gear onthe shaft 234. In this manner, as the drive shaft is rotated, the gears249 and 25$ will cause rotation of the stub shaft 252, and the worm geararrangement will rotate the shaft 234 permitting the spring 243 to pullthe staging under the tracer arm needle. A tubular sleeve 25? istelescopically mounted on the drive shaft 2% and secured to the sleeveare a plurality of spaced pinions 258, here shown as three in number andeach possessing a different diametrical size. ihe sleeve may be movedaxially on the drive shaft and as best seen in Figure 15, the pinion-sare positioned so that a selected one or" the latter may be intermeshedwith a selected one of the gears I88 on the shaft I86. I86 impartsrotation to the drum, it will be clear that the rotational speed of thelatter relative to the lineal speed of the staging may be varied so asto permit a relatively wide range of horizontal magnification ascompared to the vertical magnification of the specimen contour. Also,with this arrangement, the gears and I88 may be all placed out ofengagement whereby movement of the staging be effected withoutrotational movement of the drum.

From the foregoing description of the two embodiments of the invention,the nature of the apparatus and its method of use is believed to beclear. Numerous modifications could he made in the particularconstruction shown. particularly as to the various driving means andadjustment features, and various other mechanisms could be utilized inthe application of the teaohings made herein. Also, and by way ofexample only, a lens could be used adjacent the housing slot to increasethe amount and concentration of the light rays on the film. but isbelieved that such types of modifications will be evident to thoseskilled in the art.

Thus as the r 14 I claim:

1. Apparatus of the character described, comprising means for releasablyholding a specimen to be tested, a housing for photographic filmincluding a longitudinally extending slot therein, means in said housingfor supporting said film, means for synchronously moving said specimenand said film supporting means, a pivotally mounted lever arm, meanssecured to said levearm and engageable with the surface of said specimenas the latter is moved relative thereto, a light source from which lightrays may strike said film, and opaque means on said lever arm interposedbetween said light source and said slot whereby as said lever arm isrocked about its said pivotal mounting selected portions of said lightrays will be intercepted thereby.

2. Contour analysis mechanism comprising means for supporting an objectto be analyzed, tracing means engageable with the surface of said objectas the latter is moved relative thereto, means for moving said objectrelative to said tracing means, a lever arm secured to means forpivotally supporting said lever fect pivotal movement of said lever arm,a sheet of photographic film, a housing for said film having a slottherein, means for moving said film in timed relation to movement ofsaid object, and a light source from which said film may be exposed,said lever arm being disposed intermediate ligl t source and said filmwhereby movement of said lever arm will intercept varying portions ofsaid light.

3. Apparatus for reproducing contours of an object on photographic film,comprising a housing for said film having a longitudinally extendingslot therein, the surface of said film being disposed adjacent saidslot, means for moving said film past said slot and aligning successiveportions of the film therewith, means for supporting said object, meansfor moving said object in synchronism with the movement of said film, alever member pivotally supported and including a tracer arm engageablewith the surface of said object and arranged to follow the surfaceirregularities as the object is moved, a light source, means fordirecting light rays from said source through said slot and onto saidfilm for exposing the latter, and said lever including a portionpositioned intermediate said light source and said slot whereby as saidlever is pivoted. said slot will receive light rays along varyingportions of length, the length of such rays along said slot beingrelated to the movement of said tracer arm over the object.

l. Apparatus as set forth in claim 3 in which said pivotal support forsaid lever arm is located closer to said tracer arm than to said lightintercepting position whereby movement of said arm will be amplified bythe latter portion.

5. Apparatus for recording minute contour variations of an object onphotographic film, comprising a film housing having a longitudinallyextending slot disposed adjacent a surface of said means for moving saidfilm past said slot Within the housing, means for supporting obiect andmoving the latter in synchronism with said film, a lever arm pivotallysupported intermediate the cnds thereof and overlying said object, atracer point secured to said lever one side of said pivotal support withthe distal end thereof in intimate engagement with the surface of saidobject, a li ht source, means for directing light rays from said sourcethrough said slot and onto said film, and opaque means on said lever onthe other side of said pivotal support interposed between said lightsource and said slot, said opaque member being positioned to interceptportions of said rays and permit light rays to pass through only aportion of the length of said slot.

6. Apparatus as set forth in claim including means secured to the leveradjacent the end thereof remote from said opaque member for selectivelyvarying the pressure of said tracer point on said specimen, and meansfor selectively varying the spacing of said pivotal support relative tosaid tracer arm and to said opaque memher.

7. Apparatus for reproducing contours of an object on photographic film,comprising a housing for said film having a longitudinally extendingslot therein, a film supporting member within said housing forpositioning the surface of said film adjacent said slot, means formoving said member past said slot and aligning successive portions ofthe film therewith, means for supporting said object, means for movingsaid object in synchronism with the movement of said film supportmember, a lever member pivotally supported and including a tracer armengageable with the surface of said object and arranged to follow thesurface irregularities as the object is moved, a light source, means fordirecting light rays from said source through said slot and onto saidfilm for exposing the latter, and said lever including a portionpositioned intermediate said light source and said slot, a lensinterposed between said lever portion and said slot for receivingportions of said light rays unintercepted by said lever portion, saidlens emitting light rays toward said slot proportional to the movementof the lever.

8. Apparatus of the type described for reproducing surface contours ofan object having a generally circular cross-sectional form on a sheet ofphotographic film, comprising means for holding and rotating saidobject, a lever arm pivotally mounted and having a portion thereofengageable with the peripheral surface of said object whereby as theobject is rotated the lever arm will move in response to the elevationsand depressions on said surface, means for synchronously rotating saidobject and said film sheet, a light source for directing rays of lighttoward said film, and means on said lever arm interposed in the path ofsaid light rays for intercepting a portion of said rays in proportion tothe movement of said lever.

9. Apparatus for reproducing surface contours of an object having asubstantially circular crosssectional form on a sheet of photographicfilm or the like, comprising a film housing having a verticallyextending slot, means in said housing for supporting said film withradial portions of the surface thereof adjacent said slot, means forrotating said film past said slot, means for supporting and rotatingsaid object around a generally horizontal axis, a substantiallyhorizontal lever, a tracer arm depending from said lever and engageablewith the peripheral surface of the object, means for pivotallysupporting said lever adjacent said tracer arm, a light source fromwhich light rays may enter said slot for substantially the greaterportion of its length, said lever including an opaque portion interposedbetween said light source and said slot, said portion being spaced at agreater distance from said pivotal support than said tracer arm wherebyvertical movements of the latter will be amplified, and said portionbeing arranged to move in a generally vertical direction so as to varythe vertical portion of the slot exposed to the light rays.

10. Apparatus as set forth in claim 9 in which means are provided forselectively varying the distance between said lever pivotal support andsaid tracer arm and for vertically adjusting the height of the latter,and means for varying the moment on said lever whereby said lever armwill be gently but positively engaged with the surface periphery of saidobject.

11. Apparatus for amplifying surface variations of an object having asubstantially circular cross-sectional form and reproducing the same ona sheet of photographic film, comprising a light source, means forrotating a surface of said film past said light source wherebysequential radial portions thereof will be aligned with light rays fromsaid source, means for rotating said object in synchronism with saidfilm, a tracer arm arranged for generally vertical movement and havingthe distal end thereof in engagement with the peripheral surface of saidobject as the latter is rotated, a pivotally supported lever armcarrying said tracer arm and movable in response to motion of thelatter, said lever arm including an opaque portion disposed at a greaterdistance from said pivotal support than said tracer arm interposed inthe path of a portion of said light rays for selectively Varying theradial length of said exposed film portions in proportion to movement ofsaid tracer arm.

12. Apparatus for amplifying surface variations of an object having asubstantially circular cross-sectional form and reproducing the same ona sheet of photographic film, comprising a light source, means forrotating a surface of said film past said light source wherebysequential radial portions thereof will be aligned with light rays fromsaid source, means for rotating said object in synchronism with saidfilm, a tracer arm constantly engageable with the peripheral surface ofsaid object as the latter is rotated and movable in a generally verticaldirection in response to surface irregularities on the object, asubstantially horizontally disposed lever arm mounted for pivotalmovement and connected to said tracer arm, said lever arm including anopaque portion in the path of said light rays, and lens meansintermediate said opaque portion and said film for amplifying thevertical movement of the latter and selectively exposing greater andlesser radial portions of said film to said light rays.

13. Apparatus for amplifying surface variations of an object having asubstantially circular cross-sectional form and reproducing the same ona sheet of photographic film, comprising a substantially enclosedhousing for said film and having a longitudinally extending slottherein, means for supporting said film including a horizontallydisposed shaft, said housing having an upper and lower section, the saidsections being separable in a plane substantially coinciding with theaxis of said shaft, matching bearing means on each of said sectionswhereby said shaft and film may be removed from said housing, a secondshaft in substantial axial alignment with said first mentioned shaft,means carried by said second shaft for releasably supporting saidobject, means operatively engaged with said shafts for simultaneousrotation of the shafts, said clutch means permitting removal of saidfirst shaft from the housing, means for adjusting the axial centerlineof said object relative to said second shaft, a generally horizontallydisposed lever, pins for pivotally supporting said lever intermediatethe ends thereof, a tracer arm adjacent said pins and depending fromsaid lever for intimate engagement with the periphery of said object, alight source for directing light rays substantially perpendicularly toand for substantially the entire length of said housing slot, and anopaque mem ber carried by said lever interposed between said lightsource and said film for intercepting a portion of said light rays andvarying the length of the slot exposed to said rays.

14. Apparatus as set forth in claim 13 in which means are provided forselectively positioning said pivotal support for said lever in avertical and horizontal direction, and means independent of said lastnamed means for varying the moment on said lever.

15. Apparatus for reproducing contour irregularities of a specimen onphotographic comprising a film housing having a longitudinal slottherein for admission of light to the film, means for supporting andmoving said film past said slot, means for supporting said specimen, apiv otally supported lever including a tracer arm engageable with asurface of said specimen, means for moving said specimen along asubstantially lineal path past said tracer arm in synchronism with saidfilm moving means, a light source for emitting light rays toward saidfilm housing slot, and said lever including an o aque portion disposedin the path of a portion of said l ht rays and movable with the lever.

16. Apparatus for reproducing contour irregularities of a specimen onphotographic film, comprising a film housing having a verticallydisposed slot on a wall thereof whereby light may enter the interior ofthe housing, a drum journaled for rotation about a substantiallyvertical axis in said housing for supporting said film, horizontallydisposed staging means for supporting said specimen, a substantiallyhorizontal lever pivotally supported in superimposed relation to saidspecimen, said lever having a tracer arm engageable with the surface ofsaid specimen spaced therefrom, means for selectively varying the pathin synchronism with movement of said film supporting and moving means, atracer arm arranged for generally vertical movement and having thedistal end thereof in engagement with said object as the latter is movedtherebeneath, a pivotally supported lever carrying said tracer arm androckabie in response to movement of the latter, and said lever includingan opaque portion spaced from the pivotal support of said lever andmounted to movement With the latter, said opaque portion being disposedin the path of a portion of said light rays length of said sequentialfilm portions exposed to said light rays.

19. Apparatus as set forth in claim 18 includbetween said opaque callyamplifying the portions of said rays unint 'cepted by the opaque member.

photograph film in said housing, means for synchronously moving saidspecimen and said film supporting means, a pivotally mounted lever armhaving a portion thereof engageable with the surface of said specimen asthe latter is moved relative thereto, a light source from which lightReferences Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,048,154 Abbott July 21, 1936 2,460,726 Arndt Feb. 1, 19492,538,029 Munger Jan. 16, 1951 FOREIGN PATENTS Number Country Date547,462 Great Britain Aug. 28, 1942 717,837 Germany Feb. 24, 1942964,293 France Jan. 25, 1950

